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Feb. 16, 2010 -- Women with a history of migraines may be more likely to
develop multiple sclerosis than women without the headaches, but it is not
clear if migraines are a risk factor for the neurological disorder.

In the first large-scale study to examine the relationship between migraines
and multiple sclerosis (MS), researchers found that migraine sufferers were
roughly 50% more likely to develop MS as non-sufferers, although the overall
risk for MS was very small.

More research is needed to understand if migraines have a causal role in the
development of MS, neurologist and study researcher Ilya Kister, MD, of New
York University Medical School tells WebMD.

"We can't say if migraines slightly increase a person's chances of
developing MS, or if they are one of the early symptoms of MS," he says. "What
we can say is that individual migraine patients have little cause for panic or
concern because more than 99% of them will never develop MS."

MS and Migraines

Women are twice as likely to develop multiple sclerosis as men and three
times as likely to suffer from migraines. And both conditions are most often
diagnosed before the age of 50.

While several previous studies have shown migraines to be common among
patients being treated for MS, it has not been clear if the association was
real, Kister says.

"These studies were done in clinic populations and these populations tend to
report more symptoms in general," he says.

In an effort to better understand the prevalence and impact of migraines in
patients with MS, Kister and colleagues analyzed data from more than 116,600
female nurses participating in a nationwide health study.

The women were enrolled in the Nurses' Health Study II in 1989 and they were
followed for 16 years.

Roughly 18,000 reported a physician-diagnosed history of migraines at
enrollment and 375 were diagnosed with MS during the study.

After adjusting for other suspected risk factors for MS, having a history of
migraines was associated with a 47% increase in risk for developing the
disorder.

As yet unpublished data revealed that a diagnosis of MS was also associated
with an increased risk for developing migraines, Kister says.

His study was made public today and will be presented at the annual meeting
of the American Academy of Neurology in mid-April.

"Clearly, this is not a simple relationship," he says. "These two conditions
seem to be linked somehow, but the relationship runs both ways."

A Patient's Story

Winchester, Va., freelance writer Ann Pietrangelo has had migraines since
she was a teenager. She was diagnosed with multiple sclerosis in 2004 at the
age of 44.

"I felt there was a connection from the beginning, but I never had a doctor
who was particularly interested in discussing it," she tells WebMD. "When I go
online and talk to other people with MS it amazes me how many of them have
migraines, too."

Pietrangelo says she immediately suspected a link between her migraines and
her MS because her frequent, debilitating headaches became much less frequent
and debilitating around the time of her diagnosis.

"After a lifetime of chronic headaches -- I rarely went a week without
having at least one -- my migraines suddenly changed about six months prior to
my first MS attack," she says. "I started having fewer of them and they were
less intense."

Nicholas LaRocca, PhD, of the National Multiple Sclerosis Society calls the
NYU study interesting but preliminary.

"I think in many ways it raises more questions than it answers," he says.
"It is really hard to determine in a study like this one if migraines are a
risk factor or co-morbidity of MS."